The present invention relates to a fuel-injection valve.
An electromagnetically operable valve for injecting a fuel-gas mixture into a mixture-compressing internal combustion engine with externally supplied ignition is described in German Patent No. 195 05 886, in which a plastic gas-containing member partially encloses the downstream end of the injection valve. Within the gas-containing member, provision is made at the downstream end of the injection valve for a preparation attachment which is composed of a metallic, cup-shaped gas-containing part and a plastic insertion body. The gas can stream in between the gas-containing member and the valve housing (valve-seat support), in order to then be fed to the fuel in the preparation attachment. The plastic gas-containing member, designed partially to be quite thick-walled, is permanently joined to the actual plastic extrusion coat of the valve by the use of an integrally retaining method such as ultrasonic welding.
German Patent No. 41 21 372 describes, a fuel-injection valve for injecting a fuel-gas mixture, in which a gas-containing sleeve surrounds a nozzle body of the valve at its downstream end. In this case, the metallic gas-containing sleeve is designed in such a way that its base part is formed with a passthrough opening at an angle toward the valve end. In this manner, an annular gas gap is formed between a spray-orifice plate and the base part of the gas-containing sleeve. The gas-containing sleeve is secured to the metallic nozzle body either by several welding points, by crimping, pressing, soldering or cementing. An annular groove-shaped accommodation for a gasket for sealing with respect to a valve mount is achieved by welding an additional, costly, U-shaped retaining ring at the outer periphery of the gas-containing sleeve.
The fuel-injection valve of the present invention, has the advantage that a particularly cost-effective gas-containing member is able to be mounted at the spray-side end of the valve in a simple manner. Advantageously used to that end as the joining partner of the metallic gas-containing member is the plastic extrusion coat, customary on the conventional injection valves, which must be minimally modified only in the actual joining area compared to conventional injection valves. A simple, and nevertheless secure attachment of the gas-containing member is attained by a non-integral joining technique. Problems which can occur when using integral joining techniques, such as negative heat effects, are completely avoided in the embodiment of the present invention.
It is advantageous to manufacture gas-containing members using deep drawing, thus allowing simple production of these components in large quantities.
It is particularly advantageous to form the non-integral connection as a snap-fit, catch, or clip connection, in which projections and clips interact as corresponding connection means.
The thin-walled and tubular gas-containing member is well suited for the direct formation of annular grooves for accommodating gaskets which are used for sealing off the injection valve with respect to a valve mount. At the outer periphery of the gas-containing member, transversely to its axial extension, outwardly disposed toruses can be produced very easily by folding. It is thus possible to dispense with additional U-shaped retaining rings.